The closer the 10 lp/mm (line pairs per millimeter) curve (the thick line for low frequency) in an MTF chart to "1" of the vertical axis (the higher up), the higher the contrast reproduction performance of the tested lens will be.
The closer the 30 lp/mm curve (the thin line for high frequency) to "1" (the higher up), the higher the resolving power and thus the subjective sharpness of the lens will be.
These new teleconverters extend focal length of the master lens, making it possible to take pictures in farther ultra-telephoto ranges.
Two highly developed lens coating technologies, e BAND (Extended Bandwidth & Angular-Dependency), which uses nanotechnology, and BBAR (Broad-Band Anti-Reflection) combine to increase light transmission and to reduce flare and ghosting to imperceptible levels.
The lens delivers high contrast, sharp and clear images.
*** The circular diaphragm stays almost perfectly circular up to two stops down from maximum aperture. MTF (Modulation Transfer Function) curves describe to what extent the tested lens can faithfully reproduce contrast of the subject in images it captures.The new design adopted for the four fixed focal lens models in the SP series already on the market is essentially a fusion of engineering and style, in pursuit of functional beauty and craftsmanship by paying thorough attention to minute details.With metal used as the exterior material, a high-grade design has been created based on the design concept that emphasizes “Human Touch” characteristics, with user-friendliness considerably improved as a result. * Length is the distance from the front tip of the lens to the lens mount face.The design includes the front portion of the lens composed of curved surfaces that comfortably fit in the palm of a photographer’s hand, the focus ring and zoom ring with the groove width optimized to improve user-friendliness, the focus limiter switch allowing for easy operation, the easy-to-hold grip compatible with the Arca-Swiss type quick release system, and other features.The lens hood with smooth curves that fit the lens barrel has a design that allows for its easy attachment and removal.